Method and apparatus for downlink transmission in physical downlink control channel

1 . A method performed by a user equipment (UE), comprising:

determining at least one transmission configuration indicator (TCI) state for receiving a physical downlink shared channel (PDSCH) or an aperiodic channel state information reference signal (AP CSI-RS), wherein multiple TCI states are activated for at least one control resource set (CORESET) in an active bandwidth part (BWP) in a serving cell; and

calculating a time offset between a reception of a downlink control information (DCI) and a PDSCH corresponding to the DCI,

wherein in response to the time offset being equal to or greater than a threshold and a format of the DCI being without TCI field, determining the at least one TCI state for receiving the PDSCH comprises determining two specific TCI states of a specific CORESET used for transmitting a PDSCH.

2 . The method of claim 1 , wherein the two specific TCI states are determined for receiving the PDSCH.

3 . The method of claim 2 , wherein the UE is not configured with a parameter which indicates the UE to apply two default TCI states of single-DCI based multi-transmission reception point (TRP) transmission, or the UE is configured with the parameter and no TCI codepoint activated to the UE for PDSCH maps to two TCI states.

4 . The method of claim 2 , wherein the format of the DCI being without TCI field is configured by having no TCI present parameter for a specific CORESET used for transmitting the DCI, at least one TCI present parameter is configured for another CORESET configured in the active BWP of the serving cell, and the UE is configured with a parameter which indicates the UE to apply two default TCI states and at least one TCI codepoint activated to the UE for PDSCH maps to two TCI states.

5 . The method of claim 2 , wherein time domain resource assignment (TDRA) field in the DCI indicates an entry in a PDSCH time domain allocation list not containing a repetition number of PDSCH transmission and demodulation reference signal (DM-RS) ports indicated in the DCI are within two code division multiplexing (CDM) groups.

6 . The method of claim 2 , wherein TDRA field in the DCI indicates an entry in a PDSCH time domain allocation list containing a repetition number of PDSCH transmission, or the UE is configured by a parameter of repetition scheme as for time division multiplexing scheme and DM-RS ports indicated in the DCI are within one CDM group.

7 . The method of claim 2 , wherein the UE is configured by a parameter as first frequency division multiplexing scheme or second frequency division multiplexing scheme, DM-RS ports are indicated within a CDM group and precoding granularity is determined as wideband, and the method further comprises:

determining that first

⌈

n

PRB

2

⌉

physical resource blocks (PRBs) correspond to a first TCI state of and remaining

⌊

n

PRB

2

⌋

PRBs correspond to a second TCI state, where n PRB is a total number of allocated PRBs for the UE.

8 . The method of claim 2 , wherein the UE is configured by a parameter as first frequency division multiplexing scheme or second frequency division multiplexing scheme, DM-RS ports are indicated within a CDM group and P′ BWP.i is determined as one of values among {2, 4}.

9 . The method of claim 1 , wherein the at least one TCI state is determined for receiving the AP CSI-RS, and the method further comprises:

calculating an offset between last symbol of last PDCCH and first symbol of AP CSI-RS resource, wherein the last PDCCH carries a DCI for triggering AP CSI-RS transmission, and the AP CSI-RS resource is in a non-zero power channel state information reference signal (NZP-CSI-RS) resource set configured without a parameter of tracking reference information,

wherein the offset is less than a threshold, and determining the at least one TCI state for receiving the AP CSI-RS comprises:

determining one specific TCI state with a lowest TCI state identity number from a plurality of TCI states which is activated for a specific CORESET associated with a monitored search space, the COREST comprises a lowest CORESET identify number in a latest slot within the active BWP of the serving cell monitored by the UE.

10 . The method of claim 9 , wherein in the same symbols of the AP CSI-RS resources are without any other downlink signal, which refers to a PDSCH scheduled with a time offset larger than or equal to another threshold, having an indicated TCI state.

11 . The method of claim 1 , wherein the at least one TCI state is determined for receiving PDSCH, wherein a DCI format is without TCI field and a plurality of TCI states is activated for the CORESET used for transmitting the DCI.

12 . The method of claim 11 , wherein TDRA field in the DCI indicates an entry in a PDSCH time domain allocation list not containing a repetition number of PDSCH transmission and DM-RS ports indicated in the DCI are within two CDM groups.

13 . The method of claim 11 , wherein TDRA field in the DCI indicates an entry in a PDSCH time domain allocation list containing a repetition number of PDSCH transmission, or the UE is configured by a parameter of repetition scheme as first time division multiplexing scheme and DM-RS ports indicated in the DCI are within a CDM group.

14 . The method of claim 11 , wherein the UE is configured by a parameter as first frequency division multiplexing scheme or second frequency division scheme, DM-RS ports are indicated within a CDM group and precoding granularity is determined as wideband, and the method further comprises:

determining that first

⌈

n

PRB

2

⌉

PRBs correspond to a first TCI state and remaining

⌊

n

PRB

2

⌋

PRBs correspond to a second TCI state, where n pRB is a total number of allocated PRBs for the UE.

15 . The method of claim 11 , wherein the UE is configured by a parameter as first frequency division multiplexing scheme or second frequency division multiplexing scheme, DM-RS ports are indicated within a CDM group and P′ BWP.i is determined as one of values among {2, 4}.

16 . A user equipment (UE), comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the UE to:

determine at least one transmission configuration indicator (TCI) state for receiving a physical downlink shared channel (PDSCH) or an aperiodic channel state information reference signal (AP CSI-RS), wherein multiple TCI states are activated for at least one control resource set (CORESET) in an active bandwidth part (BWP) in a serving cell; and

calculate a time offset between a reception of a downlink control information (DCI) and a PDSCH corresponding to the DCI;

wherein in response to the time offset being equal to or greater than a threshold and a format of the DCI being without TCI field, determining the at least one TCI state for receiving the PDSCH comprises determining two specific TCI states of a specific CORESET used for transmitting a PDSCH.

17 . The UE of claim 16 , wherein the two specific TCI states are determined for receiving the PDSCH.

18 . The UE of claim 17 , wherein the UE is not configured with a parameter which indicates the UE to apply two default TCI states of single-DCI based multi-transmission reception point (TRP) transmission, or the UE is configured with the parameter and no TCI codepoint activated to the UE for PDSCH maps to two TCI states.

19 . The UE of claim 16 , wherein the at least one TCI state is determined for receiving the AP CSI-RS, and the method further comprises:

calculating an offset between last symbol of last PDCCH and first symbol of AP CSI-RS resource, wherein the last PDCCH carries a DCI for triggering AP CSI-RS transmission, and the AP CSI-RS resource is in a non-zero power channel state information reference signal (NZP-CSI-RS) resource set configured without a parameter of tracking reference information,

wherein the offset is less than a threshold, and determining the at least one TCI state for receiving the AP CSI-RS comprises:

determining one specific TCI state with a lowest TCI state identity number from a plurality of TCI states which is activated for a specific CORESET associated with a monitored search space, the COREST comprises a lowest CORESET identify number in a latest slot within the active BWP of the serving cell monitored by the UE.

20 . The UE of claim 19 , wherein in the same symbols of the AP CSI-RS resources are without any other downlink signal, which refers to a PDSCH scheduled with a time offset larger than or equal to another threshold, having an indicated TCI state.